Is there some point in the ratings of a rock where it really just becomes academic that it''s this clarity or color instead of another? Are you really just paying to know you bought a technically better rock even though it may look no better to the naked eye. Is there a consensus to how low you can go on the 3 non-size C''s and a rock will still look like a flawless-D-ideal to the average person (or girlfriend) on the street?